how to fix P0301 misfire code for my Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface, and the engine is cool.
• Disconnect the negative battery terminal to avoid electrical shorts.

2. Inspect and Replace Spark Plug

• Remove the ignition coil for cylinder 1:
  • Disconnect the electrical connector.
  • Remove the bolts securing the ignition coil.
  • Pull out the ignition coil carefully.
• Remove the spark plug:
  • Use a spark plug socket and ratchet to unscrew the spark plug from cylinder 1.
• Inspect the spark plug for signs of wear or damage.
• Replace with a new spark plug (OEM recommended type).
• Torque the new spark plug to 13 ft-lbs.

3. Inspect and Replace Ignition Coil

• If the ignition coil appears faulty or the spark plug was worn:
  • Install a new ignition coil by reversing the removal process.
  • Ensure the electrical connector is securely attached.
  • Torque the mounting bolts to 7 ft-lbs.

4. Check and Replace Fuel Injector (if necessary)

• If injector issues are suspected:
  • Disconnect the fuel injector connector for cylinder 1.
  • Remove the fuel rail if necessary, following manufacturer-specific procedures.
  • Replace the fuel injector for cylinder 1 with a new one.
  • Reassemble the fuel rail and reconnect all electrical connectors.

5. Final Checks

• Reconnect the negative battery terminal.
• Clear the engine codes using the OBD-II scanner.